Fungicides containing cymoxanil and metalaxyl

ABSTRACT

The present invention relates to the use of a compound (a), an oomycetes controlling fungicide having the structure element of formula I ##STR1## in which X is CH or N, 
     in association with 
     a compound (b), selected frm CYMOXANIL and Phosetyl-Al in combatting or preventing fungal diseases, and fungicidal composition comprising such compounds.

This is a division of application Ser. No. 827,584, filed Feb. 10, 1986, now abandoned, which in turn is a division of application Ser. No. 689,137, filed Jan. 7, 1985, now issued as U.S. Pat. No. 4,585,763, which in turn is a division of application Ser. No. 459,761, filed Jan. 21, 1983, now issued as U.S. Pat. No. 4,507,310.

The present invention relates to fungicides, more particularly to oomycetes controlling fungicides.

Although a wide variety of fungicides including various oomycetes controlling fungicides are known, the need exists for still more effective fungicides.

It has been found that the use of

(a) an oomycetes controlling fungicide having the structure element of formula I ##STR2## in which X is CH or N, in association with

(b) a compound of formula II ##STR3## hereinafter referred to by the common name CYMOXANIL or of formula III ##STR4##

hereinafter referred to by the common name Phosetyl-Al is particularly effective in combatting or preventing fungal diseases.

Aryl, as used in formula I, is intended to embrace any aromatic radical, unsubstituted or substituted, e.g. phenyl unsubstituted or substituted.

Acyl, as used in formula I, is intended to embrace any organic radical tied by a CO-group to the N-atom.

An example of a group of oomycetes controlling fungicides having the structure element of formula I (hereinafter designated compounds of formula I) suitable for use in the invention are those of formula Ia ##STR5## wherein

R₁, R₂ and R₃, independently, are H, C₁₋₄ alkyl, C₁₋₄ -alkoxy, C₁₋₄ alkylthio or halogen selected from F, Cl and Br,

A is selected from a group --CH(R₄)--R₅ or a group --N(R₆)--COOR₇,

in which

R₄ is H or C₁₋₄ alkyl, ##STR6## C.tbd.C--R₁₄, allene; or is 2,2-dihalo-1-cyclopropyl unsubstituted or substituted by C₁₋₄ -alkyl; or is phenyl unsubstituted or substituted.

R₆ is C₁₋₃ alkyl,

R₇ is C₁₋₆ alkyl, C₃₋₆ alkenyl or C₃₋₆ alkinyl, whereby R₆ and R₇ may be linked together to form CH₂ --CH₂ ;

and wherein Z and Z' are O or S

R₈ is C₁₋₆ alkyl, C₃₋₆ alkenyl, or C₃₋₆ alkinyl, and whereby ZR₈ may be linked with R₄ to form the bridge ZCH(R₁₅)--CH₂ in which Z is as defined above and R₁₅ is H or CH₃ ;

R₉, R'₉ and R"₉ are H or C₁₋₄ alkyl,

R₁₀, R'₁₀ and R"₁₀ are C₁₋₄ alkyl, whereby R₉ may be linked with R₁₀, resp. R'₉ with R'₁₀, resp. R"₉ with R"₁₀ and signify alkylene, to form a 5- or 6-membered heterocyclic ring,

R₁₁, R₁₂, R₁₃, independently, are H, C₁₋₄ -alkyl, or halogen selected from F, Cl or Br,

R₁₄ is H, C₁₋₄ alkyl or halogen selected from Cl, Br or I,

and Y is H;

a hydrocarbon selected from C₁₋₆ alkyl,

C₂₋₆ alkenyl and C₂₋₆ alkinyl unsubstituted or substituted by halogen, selected from F, Cl or Br, or by CN;

C₂₋₆ epoxyalkylene; C₃₋₆ cycloalkyl; a 5-membered heterocyclic ring comprising 1 to 3 heteroatoms selected from O, S and N, which is unsubstituted or substituted by C₁₋₄ alkyl or halogen selected from F, Cl or Br;

(A₁)_(n) --Az; (A₁)_(n) --Y₁ --NR_(9a) R_(10a) ;

(A₁)_(n) Z₁ H and esters or ethers thereof;

benzyl unsubstituted or substituted, in which

A₁ is CH₂ or CH(CH₃)

n is 0 or 1,

Az is a 1-azolyl comprising 1 to 3 nitrogen atoms,

Y₁ is a covalent bond or NH,

R_(9a) is H or C₁₋₄ alkyl,

R_(10a) is C₁₋₄ alkyl,

Z₁ is O or S.

Where any of R₁, R₂, R₃ and R₄ is or comprises C₁₋₄ alkyl, this is preferably CH₃.

Where R₅ is 2,2-dihalo-1-cyclopropyl both halogens comprised therein signify F, Cl or Br, particularly Cl or Br, especially Cl; both halogens are preferably identical. Any C₁₋₄ alkyl substituent of 2,2-dihalo-1-cyclopropyl signifies preferably CH₃.

Where R₅ is substituted phenyl, it is conveniently mono- or disubstituted. Suitable substituents of phenyl are e.g. C₁₋₄ alkyl (CH₃), C₁₋₄ alkoxy (OCH₃) and halogen (F, Cl, Br).

R₆ is preferably CH₃.

Where any of R₇ and R₈ is C₁₋₆ alkyl, it is conveniently C₁₋₃ -alkyl, preferably CH₃.

Where any of R₉, R'₉, R"₉, R₁₀, R'₁₀ and R"₁₀ is C₁₋₄ alkyl, it is e.g. CH₃.

Where R₉ and R₁₀, resp. R'₉ and R'₁₀ resp. R"₉ and R"₁₀ are linked together and represent alkylene, such alkylene is conveniently unbranched.

Where any of R₁₁, R₁₂ and R₁₃ is C₁₋₄ alkyl, this is preferably CH₃.

Where any of R₁₁, R₁₂ and R₁₃ is halogen, this is preferably Cl or Br, particularly Cl.

Where R₁₄ is C₁₋₄ alkyl, this may be straight or branched and signifies for example CH₃.

Where Y is hydrocarbon substituted by halogen, such halogen is conveniently Cl or Br.

Where Y is substituted hydrocarbon, the hydrocarbon signifies preferably C₁₋₆ alkyl, particularly C₁₋₃ alkyl.

Where Y is C₁₋₆ alkyl, unsubstituted, it is preferably C₃₋₅ -alkyl, particularly unbranched C₃₋₅ alkyl or 2-methyl-1-butyl.

Where Y is C₃₋₆ alkenyl, it is preferably CH═CH--CH₃.

Where Y is C₃₋₆ cycloalkyl, it is preferably cyclopropyl or cyclobutyl.

Where Y is a 5-membered heterocycle, this may be aromatic oder hydrogenated; examples of suitable heterocyclic radicals are furyl (e.g. 2-furyl), tetrahydrofuryl, thienyl, isoxazyl and thiadiazolyl. Suitable substituents of such heterocyclic groups are particularly Cl, Br, CH₃. Any substituted heterocycle is particularly mono-substituted.

Suitable significances of Az are e.g. pyrazol-1-yl, imidazol-1-yl and 1H-1,2,4-triazol-1-yl.

Where R_(9a) is C₁₋₄ alkyl, this is especially CH₃ or C₂ H₅.

R_(10a) signifies preferably CH₃.

Suitable examples of compounds of formula Ia, wherein Y is esterified (A)_(n) Z₁ H are esters with an alkane carboxylic acids (such as CH₃ COOH), an alkane sulfonic acid (e.g. CH₃ SO₂ OH), a dialkylsulfamic acid (e.g. (CH₃)₂ NSO₂ OH), a functional derivative of a carbonic acid etc.

Suitable examples of compounds of formula Ia, wherein Y is etherified (A₁)_(n) Z₁ H are e.g. compounds of formula Ia, wherein Y is (A₁)_(n) Z₁ W, in which A₁, n and Z₁ are as defined above and W is a group selected from C₁₋₈ alkyl (particularly CH₃, C₂ H₅), C₃₋₆ -alkenyl (particularly CH₂ --CH═CH₂), C₃₋₆ alkinyl (particularly CH₂ C.tbd.CH), C₁₋₄ alkoxy-C₁₋₃ alkyl (particularly CH₂ OCH₃), C₁₋₄ alkylthio-C₁₋₃ -alkyl (particularly CH₂ SCH₃) unsubstituted or substituted by halogen (F, Cl, Br) or a pyranyl group.

Preferred compounds of formula Ia have one or more of the following features:

at least one of R₁, R₂, R₃ is different from H,

R₃ is hydrogen, 3-Cl or 3-Br,

R₁ is in the 2-position,

R₁ and R₂ are in the 2,6-position,

R₁ and R₂ are selected from H, CH₃, Cl and OCH₃,

R₁ and R₂ are identical,

R₁ and R₂ are CH₃ in the 2,6-position and R₃ is H, 3-Cl or 3-Br,

X is CH(R₄)COZR₈, N(CH₃)--COOC₁₋₆ alkyl, or 2-oxo-3-oxazolidinyl,

Z and Z' are O,

R₈ is C₁₋₆ alkyl,

R₈ is linked with R₄ to form CH₂ CH₂,

Y is CH₂ OH, CH₂ OCH₃, CH₂ OC₂ H₅, CH₂ O--CH₂ --CH═CH₂, CH₂ O--CH₂ --C.tbd.CH, CH₂ --OCH₂ OCH₃, CH₂ OSO₂ N(CH₃)₂, CH₂ Cl, n--C₄ H₉, cyclopropyl, CH═CH--CH₃, 2-furyl, benzyl, 2-tetrahydrofuryl.

A preferred sub-group of compounds of formula Ia, are compounds of formula Ib ##STR7## wherein

X is as defined above,

either

R_(a) and R_(b) are both H or together form a covalent bond

Y_(a) is C₃₋₅ alkenyl; CH₂ OC₁₋₅ alkyl; CH₂ --OC₃₋₆ alkenyl; CH₂ --OC₃₋₆ alkinyl; furyl; benzyl; CH₂ Cl or C₃₋₆ cycloalkyl,

either

R₁ ' and R₂ ' are both CH₃ in the 2- and 6-positions or R₁ ' is 3-Cl and R₂ ' is H, and R₃ ' is H, CH₃, Cl or Br.

Where Y_(a) is CH₂ OC₁₋₅ alkyl, this is preferably CH₂ OCH₃.

Where Y_(a) is C₃₋₆ cycloalkyl, this is preferably cyclopropyl.

Where Y_(a) is furyl, this is preferably 2-furyl.

Where Y_(a) is CH₂ OC₃₋₆ alkenyl, this is preferably CH₂ Oallyl or --CH₂ O--(2-butenyl).

Where Y_(a) is CH₂ OC₃₋₆ alkinyl, this is preferably CH₂ O(2-propinyl).

Where in the compounds of formula I R₃ ' is Cl, Br or CH₃ this is preferably in the 3-position, particularly when R₁ ' and R₂ ' are 2- and 6-CH₃ resp.

Examples of valuable oomycetes controlling fungicidal compounds of formula Ib are those wherein X, R_(a), R_(b), Y_(a), R₁ ', R₂ ' and R₃ ' are

(i) CH, H, H, 2-furyl, 2-CH₃, 6-CH₃ and H resp. (common name furalaxyl)

(ii) CH, H, H, CH₂ --OCH₃, 2-CH₃, 6-CH₃ and H resp. (common name metalaxyl)

(iii) CH, H, H, benzyl, 2-CH₃, 6-CH₃ and H resp. (common name galben)

(iv) CH, covalent bound (R_(a) +R_(b)), CH₂ Cl, 2-CH₃, 6-CH₃ and H (common name milfuram)

(v) N, covalent bound (R_(a) +R_(b)), CH₂ --OCH₃, 2-CH₃, 6-CH₃ and H (hereinafter designated compound I)

(vi) N, covalent bound (R_(a) +R_(b)), CH₂ --OCH₃, 2-CH₃, 6-CH₃, 3-Cl

(vii) N, covalent bound (R_(a) +R_(b)), CH₂ -- OCH₃, 2-CH₃, 6-CH₃, 3-Br

(viii) CH, covalent bound (R_(a) +R_(b)), cyclopropyl, 3-Cl, H and H.

(ix) CH, covalent bound (R_(a) +R_(b)), CH₂ OCH₃, 2-CH₃, 6-CH₃ and H.

Compounds of formula I are known or may be obtained according to known processes.

Cymoxanil and Phosetyl-Al are also known systemic fungicides having a fungicidal effect against Plasmopara spp and Phytophthora spp.

It has been found, that the use of Cymoxanil or Phosetyl-Al in combination with a compound of formula I particularly one of formula Ia, more particularly one of formula Ib, e.g. one of the compounds (i) to (ix) indicated above, surprisingly and substantially enhances the effectiveness of the latter against such fungi, and vice versa. The risk of fungi developing resistance against oomycetes controlling having the structure element of formula I is also significantly decreased when using them in association with Cymoxanil or Phosetyl-Al. Moreover, the method of the invention is also surprisingly active against acylalanine resistant field strains of Phytophthora spp and Plasmopara spp as indicated i.a. by a significant decrease of the factor of resistance (the ratio of the fungicidal activity at the 90% level against resistant and sensitive strains). The term "acylalanine resistant field strains" as used herein means oomycetes that developed resistant against acylalanine type fungicides (see e.g. Resistant to acylalanine-type fungicides in Peronosporales, Phytopathology 71(5) 558 (1981). Finally, the method of the invention is effective against a wider spectrum of fungi than that that can be combatted with the active ingredients of this method when used solely.

Accordingly, the invention provides an improved method of combatting fungi, particularly fungi of the class Oomycetes such as Phytophthora spp., Plasmopara spp., Peronospora spp., Pseudo-peronospora spp., Sclerophthora spp., Bremia spp. and Pythium spp., in crop locus, especially in grapevines, tomato, hops, cacao, tobacco, potato and lettuce cultures, and an eucalyptus locus which comprises applying to the locus, in admixture or separately, a fungicidally effective aggregate amount of a compound of formula I and Cymoxanil or Phosetyl-Al.

The term crop as used herein is intended to embrace any desired plant growth.

Preferably the compounds of formula I are applied at a rate of 100-400 g/ha, particularly 150-300 g/ha, e.g. 200 g/ha in association with 40-160 g/ha, particularly 60-120 g/ha, e.g. 80 g/ha Cymoxanil or 750-2500 g/ha, particularly 1000-2000 g/ha, e.g. 1500 g/ha Phosetyl-Al.

Other pesticides e.g. fungicides, bactericides, insecticides, acaricides, herbicides or plant growth regulating agents may be used in addition to the above associated active ingredients, to enhance the activity of the association of the invention or to widen its spectrum of activity; it is particularly advantageous to use an additional contact fungicide in the method of the invention.

Contact fungicides particularly indicated for use together with the association of the invention are one or more fungicides selected from a copper fungicide, e.g. cuprous oxide, copper (II) oxychloride, cupric hydroxide, copper (II) calcium sulphate, copper (II) calcium oxychloride, Bordeaux mixture or Burgundy mixture; captan; dichlofluanid; folpet; mancozeb; maneb; zineb; chlorothalonil; propineb and dithianon or mixture thereof. Such additional contact fungicide(s) may in general be applied at a rate of 200-2000 g/ha. Mancozeb is particularly appropriate for use in the method of this invention. It has an additional synergistic effect on the compound of formula I combinations with Cymoxanil or Phosetyl-Al.

The invention also provides fungicidal compositions comprising a compound of formula I and Cymoxanil or Phosetyl-Al.

In the composition of the invention the weight ratio compound of formula I: Cymoxanil lies preferably in the range of 10:1 to 1:3, more preferably 5:1 to 1:1, particularly 4:1 to 2:1 e.g. 2.5:1. The synergistic effect is evident from the various experimental data in the tables hereinafter, where synergism is i.a. illustrated for the weight ratio compound of formula I: Cymoxanil in the range 1:0.3 to 1:3.

In the compositions of the invention the weight ratio compound of formula I: Phosetyl-Al lies preferably in the range of 1:25 to 1:2, more preferably in the range of 1:15 to 1:3, particularly 1:10 to 1:5 e.g. 1:7.

Where the compositions of the invention comprise additionally a contact fungicide, the weight ratio compound of formula I: contact fungicide lies preferably in the range of 1:2 to 1:10, and where Mancozeb, Folpet, Captan or Maneb are used, more preferably 1:4 to 1:9, particularly 1:5 to 1:8 e.g. 1:7. It is particularly advantageous to incorporate Mancozeb in the compositions of the invention.

The composition of the invention may be employed in any conventional form, for example in the form of a twin pack, an instant granulate, a flowable or a wettable powder in association with fungicidally acceptable diluents. Such compositions may be produced in conventional manner, e.g. by mixing the active ingredients with a diluent (carrier) and other formulating ingredients such as surfactants.

The term diluents as used herein means any liquid or solid agriculturally acceptable material which may be added to the active constituents to bring it in an easier or improved applicable form, respectively to a usable or desirable strength of activity. It can for example be talc, kaolin, diatomaceous earth, xylene, or water.

Particularly formulations to be applied in spraying forms such as water dispersible concentrates or wettable powders may contain surfactants such as wetting and dispersing agents, e.g. the condensation product of formaldehyde with naphthalene sulphonate, an alkylarylsulphonate, a lignin sulphonate, a fatty alkyl sulphate, an ethoxylated alkylphenol and an ethoxylated fatty alcohol.

In general, the formulations include from 0.01 to 90% by weight of active agent from 0 to 20% fungicidally acceptable surfactant and 10 to 99.99% solid or liquid diluent(s), the active agent consisting of at least one compound of formula I together with Cymoxanil or Phosetyl-Al, and optionally other active agents, particularly contact fungicides. Concentrate forms of compositions generally contain between about 2 and 80%, preferably between about 5 and 70% by weight of active agent. Application forms of formulation may for example contain from 0.01 to 20% by weight, preferably from 0.01 to 5% by weight of active agent.

The invention is illustrated by the following Examples wherein parts and percentages are by weight and temperatures are in °C.

TEST A Fungicidal effect against Phytophthora infestans strains resistant against acylalanine type fungicides

Yound potted tomato or potato plants (3-5 leaf stage) are sprayed with an aqueous spray liquid of

mixture A,

containing 0.05 to 0.0002% compound of formula I and 0.05 to 0.0002% CYMOXANIL,

or mixture B,

containing 0.05 to 0.0002% compound of formula I and 2 to 0.2% Phosetyl-Al

or mixture C,

containing 0.05 to 0.0002% compound of formula I and 0.2 to 0.003% of a contact fungicide such as Mancozeb, Folpet, Captan, dichlofluanid, Maneb or copper fungicides.

Two hours (or 4, 8, 16, 32 or 64 hours later) the treated plants or leaves thereof are washed vigorously, e.g. by simulated rain washing at a rain rate of 10-50 mm/hour. Two hours after the washing procedure, the treated plants or leaves are inoculated with a spore suspension (10⁵ sporangia/ml) of Phytophthora infestans strains that developed resistance against compounds of formula I. The plants are then transferred to a tent providing 100% relative atmospheric humidity at an ambient temperature of 16° and a day length of 16 hours. Disease control is evaluated 4-5 days thereafter, by comparing the treated plants (leaves) with untreated, similarly inoculated plants (leaves). Where, with the mixtures A and B complete control of the fungal infestation is observed, the degree of fungicidal activity provided by mixture C is significantly less pronounced. Similar results are obtained in grape vines against Plasmopara viticola strains which are resistant against acylalanine type fungicides.

TEST B Synergistic activity

In this test, the fungicidal acitvity provided by the compounds of formula I, CYMOXANIL or Phosetyl-Al alone, is compared with the activity provided by a compound of formula I when used in association with CYMOXANIL or Phosetyl-Al. The presence of an eventual synergistic effect between two active ingredients is then established with the aid of the Colby equation ##EQU1## wherein A and B are the fungicidal activities of the active ingredients when used alone and p is the fungicidal activity that theoretically would have been obtained with the mixture if there was no interaction between the active ingredients. If p is lower than the experimentally established fungicidal effect, there is synergism.

Young potted potato plants are sprayed with an aqueous spray liquid containing either a compound of formula I, CYMOXANIL or Phosetyl-Al alone or in the association according to the invention. The compounds of formula I and CYMOXANIL are applied in concentrations of 0.0125 to 0.00002%, Phosetyl-Al in concentrations of 0.8 to 0.0125%, until the run-off.

Two hours later, the treated plants are inoculated with a spore suspension of Phytophthora infestans and the plants are then transferred to a tent providing 100% relative atmospheric humidity at an ambient temperature of 16° C. and a day length of 16 hours. Disease control is evaluated 4-5 days later by comparing the treated plants with untreated, similarly inoculated plants. Analogous tests are run using grape plants infested with Plasmopara viticola.

A more than additive effect is obtained as illustrated in the following tables, in which Comp. is Compound I, Cym is Cymoxanil, Phos. is Phosetyl-Al, M is Mancozeb, the underlined figures are p(Colby) and the non-underlined figures are the experimentally established fungicidal effect.

                  TABLE I                                                          ______________________________________                                         Phytophthora/Tomato                                                            ppm                                                                                     Comp.                                                                 Cym.       0        2         8       32                                       ______________________________________                                         0           0        60        80     100                                      2          10        80 .sub.--.sub.64                                                                        90 .sub.--.sub.82                                                                     100                                      8          40       100 .sub.--.sub.76                                                                       100 .sub.--.sub.88                                                                     100                                      32         60       100 .sub.--.sub.84                                                                       100 .sub.--.sub.92                                                                     100                                      ppm                                                                            ______________________________________                                    

                  TABLE II                                                         ______________________________________                                         Phytophthora/Tomato                                                            ppm                                                                                    Comp.                                                                  Cym.      0       0.2     0.6    1.8    5.4                                    ______________________________________                                         0          0       0      20     40      70                                    0.2        0      10 .sub.--.sub.0                                                                       30 .sub.--.sub.20                                                                     50 .sub.--.sub.40                                                                      90 .sub.--.sub.70                     0.6        0      20 .sub.--.sub.0                                                                       30 .sub.--.sub.20                                                                     60 .sub.--.sub.40                                                                      90 .sub.--.sub.70                     1.8       20      20 .sub.--.sub.20                                                                      40 .sub.--.sub.36                                                                     65 .sub.--.sub.52                                                                     100 .sub.--.sub.76                     5.4       40      40 .sub.--.sub.40                                                                      60 .sub.--.sub.52                                                                     80 .sub.--.sub.64                                                                     100 .sub.--.sub.82                     ppm                                                                            ______________________________________                                    

                  TABLE III                                                        ______________________________________                                         Phytophthora/Tomato                                                            ppm                                                                                      Comp.                                                                Phos.       0       2         8       32                                       ______________________________________                                          0           0       60        80     100                                      125         20       70 .sub.--.sub.68                                                                        90 .sub.--.sub.84                                                                     100                                      500         50       90 .sub.--.sub.80                                                                       100 .sub.--.sub.90                                                                     100                                      2000        70      100 .sub.--.sub.88                                                                       100 .sub.--.sub.94                                                                     100                                      ppm                                                                            ______________________________________                                    

                  TABLE IV                                                         ______________________________________                                         Phytophthora/Potato                                                            ppm                                                                                      Comp.                                                                Phos.       0       2         8       32                                       ______________________________________                                          0           0       50        80     100                                      125         10       60 .sub.--.sub.54                                                                        80 .sub.--.sub.82                                                                     100                                      500         30       80 .sub.--.sub.65                                                                       100 .sub.--.sub.86                                                                     100                                      2000        80      100 .sub.--.sub.90                                                                       100 .sub.--.sub.96                                                                     100                                      ppm                                                                            ______________________________________                                    

                  TABLE V                                                          ______________________________________                                         Plasmopara/grape vine                                                                  Comp.                                                                  Cym.      0       0.2     0.6    1.8    5.4                                    ______________________________________                                         ppm                                                                            0          0       0      30      50     60                                    0.2        0      30 .sub.--.sub.0                                                                       40 .sub.--.sub.30                                                                      55 .sub.--.sub.50                                                                     70 .sub.--.sub.60                     0.6       20      40 .sub.--.sub.20                                                                      50 .sub.--.sub.44                                                                      60 .sub.--.sub.60                                                                     80 .sub.--.sub.68                     1.8       50      50 .sub.--.sub.50                                                                      80 .sub.--.sub.65                                                                      90 .sub.--.sub.75                                                                    100 .sub.--.sub.80                     5.4       60      60 .sub.--.sub.60                                                                      90 .sub.--.sub.72                                                                     100 .sub.--.sub.80                                                                    100 .sub.--.sub.84                     ppm                                                                            ______________________________________                                    

                  TABLE VI                                                         ______________________________________                                         Plasmopara/grape vine                                                                  Comp.                                                                  Phos.     0       0.2     0.6    1.8    5.4                                    ______________________________________                                         ppm                                                                             0         0       0       0     40     50                                     10        10      10 .sub.--.sub.10                                                                      30 .sub.--.sub.28                                                                     50 .sub.--.sub.46                                                                     60 .sub.--.sub.55                      30        20      20 .sub.--.sub.20                                                                      40 .sub.--.sub.36                                                                     60 .sub.--.sub.52                                                                     70 .sub.--.sub.60                      90        40      40 .sub.--.sub.40                                                                      60 .sub.--.sub.52                                                                     70 .sub.--.sub.64                                                                     80 .sub.--.sub.70                      270       50      50 .sub.--.sub.50                                                                      70 .sub.--.sub.60                                                                     80 .sub.--.sub.70                                                                     90 .sub.--.sub.75                      ppm                                                                            ______________________________________                                    

                  TABLE VII                                                        ______________________________________                                         Phytophthora/Tomato                                                                   Comp.                                                                          0     0.125   0.375    1.13  3.38 ppm                                          M                                                                       Cym.     0       0.9     2.7    8.1   24.3 ppm                                 ______________________________________                                         0         0      10      20      40    60                                      0.1       0      2.5 .sub.--.sub.10                                                                     30 .sub.--.sub.20                                                                      50 .sub.--.sub.40                                                                    80 .sub.--.sub.60                       0.3       0      35 .sub.--.sub.10                                                                      40 .sub.--.sub.20                                                                      60 .sub.--.sub.40                                                                    90 .sub.--.sub.60                       0.9      20      45 .sub.--.sub.28                                                                      50 .sub.--.sub.36                                                                      70 .sub.--.sub.52                                                                   100 .sub.--.sub.68                       2.7      35      50 .sub.--.sub.41                                                                      55 .sub.--.sub.48                                                                     100 .sub.--.sub.61                                                                   100 .sub.--.sub.74                       ppm                                                                            ______________________________________                                    

                  TABLE VIII                                                       ______________________________________                                         Plasmopara/grape vine                                                                 Comp.                                                                          0     0.125   0.375    1.13  3.38 ppm                                          M                                                                       Cym.             0.9     2.7    8.1   24.3 ppm                                 ______________________________________                                         0         0      30       50     60    70                                      0.1       0      30 .sub.--.sub.30                                                                       60 .sub.--.sub.50                                                                     70 .sub.--.sub.60                                                                   100 .sub.--.sub.70                       0.3      20      50 .sub.--.sub.44                                                                       70 .sub.--.sub.60                                                                     80 .sub.--.sub.68                                                                   100 .sub.--.sub.76                       0.9      40      60 .sub.--.sub.58                                                                       80 .sub.--.sub.70                                                                    100 .sub.--.sub.76                                                                   100 .sub.--.sub.82                       2.7      60      80 .sub.--.sub.72                                                                      100 .sub.--.sub.80                                                                    100 .sub.--.sub.84                                                                   100 .sub.--.sub.88                       ppm                                                                            ______________________________________                                    

Based on the results in Table I-VIII--which indicate a synergism--the factor of synergism can be calculated with the aid of the Wadley equations: ##EQU2## wherein a, b, etc. are the weight ratios at which the active ingredients are used in the mixture; EC 90, EC 90 (exp.) and EC' (theor.) the concentrations allowing a 90% fungicidal control resp. of the active ingredient when used alone as determined by experiment, of the tested composition as determined by experiment and of the tested composition as calculated. SF is the factor of synergism (in case of synergism it is ≧1).

The factor of synergism (SF) found with mixtures of Compound I/Cymoxanil and of Compound I/Cymaoxanil/Mancozeb resp. tested on tomato (Phytophthora infestans) and grape vine (Plasmopara viticola) under greenhouse conditions, calculated according to Wadley, are given:

                  TABLE IX                                                         ______________________________________                                                 Tomato (Phyt.)                                                                               Grape vine (Plasm.)                                              EC 90.sup.(2)     EC 90.sup.(2)                                                theor. exp.   SF.sup.(2)                                                                             theor.                                                                               exp.  SF.sup.(2)                           ______________________________________                                         Comp./Cym.sup.( *.sup.)                                                        1:0       --       17           --    19                                       1:0.3     21        7     3.0   23    11    2.1                                1:1       31       10     3.1   26     5    5.2                                1:3       49       16     3.1   30     4    7.5                                0:1                125                36                                       Comp./Cym/M                                                                    1:0.3:7   69       29     2.4   49    16    3.1                                1:2.4:7   76       32     2.4   46     6    7.7                                ______________________________________                                          .sup.(*.sup.) weight ratio                                                     .sup.(2) see Wadley                                                      

    ______________________________________                                                      Formulation Examples                                                           (Wettable powders)                                                             A    B     C     D   E   F   G    H                                            % by weight                                                       ______________________________________                                         Compound of formula I                                                                         8.     10     7  10  40   7  10   25                            (e.g. Compound 1)                                                              CYMOXANIL      3.2     5    --  10  24  --  5    10                            Phosetyl-Al    --     --    50  --  --  50  --   --                            Contact fungicide e.g.              --  --       --                            Mancozeb       56     25    --  --          25                                 Copper (II) oxychloride                                                                       --     10    --  --          17.5                               Copper (II) calcium                                                                           --      5    --  --          18.5                               sulphate                                                                       Folpet         --     --    23  30          --                                 Surfactant:                                                                    Wetting agent (e.g.                                                                           1       1     1   1   1   1  1     1                            Na alkyl naphthalene                                                           sulphonate)                                                                    Dispersing agent (e.g.                                                                        5       5     5   5   5   5  5     5                            Na lignin sulphonate)                                                          Diluent:                                                                       Silica         5       5     5   5   5   5  5     5                            Kaolin         21.8   34     9  39  25  28  13   54                            Prussian blue  --     --    --  --  --   4  --   --                            ______________________________________                                    

The formulations are obtained by mixing the components, subsequently milling the mixture and a second mixing in conventional manner.

In general, the active ingredients are used in technical form. An example of a formulation comprising technical active ingredients is as follows:

Example J

    ______________________________________                                         Compound I technical (95%)                                                                             10.5%                                                  Cymoxanil - technical (95%)                                                                             5.3%                                                  Mancozeb - technical (80%)                                                                             31.3%                                                  Copperoxy (II) chloride (57% Cu)                                                                       17.5%                                                  Copper (II) calcium sulphate (27% Cu)                                                                  18.7%                                                  Surfactant and Silica   11.0%                                                  Kaolin                   5.7%                                                  ______________________________________                                    

Example K--Flowable 440 g/l

    ______________________________________                                         4.2% w/w    Compound I techn. 95%                                              1.7% w/w    Cymoxanil techn. 95%                                               35.0% w/w   Mancozeb techn. 80%                                                4.0% w/w    Surfactant                                                         6.0% w/w    1,2-Propylene glycol (Anti-freezing)                               0.3% w/w    Sticker                                                            0.5% w/w    Stabilisator (e.g. citric acid)                                    48.3% w/w   Water                                                              100.0% w/w                                                                     ______________________________________                                    

The formulation is produced by mixing the components, wet grinding and mixing.

Example L--Granules 67% w/w WG

    ______________________________________                                         8.4% w/w                                                                               Compound I techn. 95%                                                  3.4% w/w                                                                               Cymoxanil techn. 95%                                                   70.0% w/w                                                                              Mancozeb techn. 80%                                                    10.0% w/w                                                                              Dispersing/binding agent (e.g. Na--lignin-sulfonate)                   7.7% w/w                                                                               Diluent (e.g. kaolin)                                                  0.5% w/w                                                                               Stabilisator (e.g. citric acid).                                       ______________________________________                                    

The formulation is produced by mixing and grinding the components followed by pan-granulation or fluid bed-granulation.

The granules disperse well in water, forming a sprayable suspension. 

What is claimed is:
 1. A fungicidal composition comprising a component (a) of the formula I, ##STR8## and a component (b) which is cymoxanil; the weight ratio of component (a) to component (b) being in the range of from 10:1 to 1:1.
 2. A composition according to claim 1 in which the weight ratio of component (a) to component (b) is within the range of from 5:1 to 1:1.
 3. A composition according to claim 2 in which the weight ratio of component (a) to component (b) is 4:1 to 2:1.
 4. The method of combatting Oomycetes fungus in a crop locus comprising applying to said locus a fungicidally effective amount of a compostion of claim
 1. 5. The method according to claim 4 in which the Oomycetes fungus to be combatted is resistant to said component (a).
 6. The method according to claim 5 in which component (a) is applied at a rate of from 100 to 400 g/ha and component (b) is applied at a rate from 40 to 160 g/ha.
 7. The method according to claim 4 in which the weight ratio of component (a) to component (b) is within the range from 5:1 to 1:1.
 8. The method according to claim 7 in which component (a) is applied at a rate of from 150 to 300 g/ha and component (b) is applied at a rate of from 60 to 120 g/ha.
 9. The method according to claim 5 in which the weight ratio of component (a) to component (b) is within the range from 5:1 to 1:1.
 10. The method according to claim 9 in which component (a) is applied at a rate of from 150 to 300 g/ha and component (b) is applied at a rate of from 60 to 120 g/ha.
 11. The method according to claim 4 in which the fungus to be combatted is Phytophthora spp or Plasmopara spp.
 12. The method according to claim 5 in which the fungus to be combatted is Phytophthora spp or Plasmopara spp. 